<form id="frmCaptcha" name="frmCaptcha">
<table> 
  <tr>
    <td align="left">
      <label for="captcha">Captcha</label>
    </td>
    <td>
      <input id="txtCaptcha" type="text" name="txtCaptcha" value="" maxlength="10" size="32" />
    </td>
    <td> 
      <img id="imgCaptcha" src="createImage.php" />
    </td>
  </tr>
  <tr>
    <td>&nbsp;</td>
    <td>
      <input id="btnCaptcha" type="button" value="Captcha Test" name="btnCaptcha" 
          onclick="getParam(document.frmCaptcha)" />
    </td>
  </tr>
</table> 
<script language="JavaScript" type="text/javascript" src="ajax_captcha.js"></script>
<div id="result">&nbsp;</div>
</form>